@@ -41,10 +41,9 @@ Figure~\ref{fig:control1} shows the command signal used to show the time that pa
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@@ -41,10 +41,9 @@ Figure~\ref{fig:control1} shows the command signal used to show the time that pa
Some previous works cited in section~\ref{sec:related} discuss the TTFF but none of them does it by looking in detail at the technology of the GPS~\cite{bib:entracked-datadriven-modeling}~\cite{bib:feasibility-duty-cycling}~\cite{bib:accuracy-adaptation}. The performances are evaluated for smartphones looking at how much time it takes for an application to get a position measure after the API request \textcolor{red}{??}. An important remark is that GPS sensors in smartphones implement the so called Assisted-GPS that allows the retrieval of the ephemeris data from the internet instead of listening to the satellites. The model presented in this paper can be adapted to reprent this allowing for an external input that triggers the transition \texttt{get\_ephemeris}, possibly before the delay that represent the action of listening instead to the satellites.
Some previous works cited in section~\ref{sec:related} discuss the TTFF but none of them does it by looking in detail at the technology of the GPS~\cite{bib:entracked-datadriven-modeling}~\cite{bib:feasibility-duty-cycling}~\cite{bib:accuracy-adaptation}. The performances are evaluated for smartphones looking at how much time it takes for an application to get a position measure after the API request \textcolor{red}{??}. An important remark is that GPS sensors in smartphones implement the so called Assisted-GPS that allows the retrieval of the ephemeris data from the internet instead of listening to the satellites. The model presented in this paper can be adapted to reprent this allowing for an external input that triggers the transition \texttt{get\_ephemeris}, possibly before the delay that represent the action of listening instead to the satellites.
Being aware of those differences -- the extra software layers included in the experiments and the fact that are used Assisted-GPS sensors -- the results are coherent with what discussed here. Our model achieves on the other side more generality not being dependent on the specific implementation on the given device. Moreover it allows to look directly at what are the theoretical performances we should expect from a GPS sensor without the overhead that is introduced by the operative system of a smartphone.
Up to the limited extent to which they are comparable -- due to the extra software layers included in the experiments and the fact that are used Assisted-GPS sensors -- the results are coherent with what discussed here. Our model on the other side achieves more generality not being dependent on the specific implementation on the given device. Moreover it allows to look directly at what are the theoretical performances we should expect from a GPS sensor without the overhead that is introduced by the operative system of a smartphone.
